Electrolyte effects on enzyme electrochemistry

Abstract

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights  The effect of electrolytes in bioelectrochemistry is presented.  The Hofmeister effect and the most recent experimental and theoretical work on specific ion effects are described.  The research challenges and the importance of choosing the most appropriate electrolyte for bionsensors and biofuel cells have been reviewed.

Review—Quantification of Hydrogen Peroxide by Electrochemical Methods and Electron Spin Resonance Spectroscopy

“…223,[258][259][260][261][262][263][264][265][266][267][268] It is finally worth to mention that protein-modified electrodes are associated with some disadvantages such as: (i) preparation of the electrodes is time-consuming, as they have to be frequently renewed; (ii) preparation might be expensive in the case of a high price protein; (iii) activity of the enzyme can rapidly decrease because of denaturation; (iv) enzyme orientation on the electrode surface might be incorrect leading to impairment of catalytic activity; 227,269,270 (v) electrolytes in the measuring buffer may affect the activity, especially of redox enzymes. 271 Another particular electrode type and measuring concept needs to be pointed out here. The research group of Li et al 272 described fabrication of an electrochemical sensor with a sensitivity for H 2 O 2 of 10 fM, and a linear response from 100 pM to 10 nM.…”

Specific Buffer Effects on the Intermolecular Interactions among Protein Molecules at Physiological pH

“…Ions play particular key roles in nature which have only been partially understood. − Specific ion effects were first observed by Hofmeister in 1888 who studied the salt-induced aggregation of egg white proteins. , This finding led to a myriad of studies devoted to investigate and rationalize ion specificity in solution chemistry, biochemistry, and colloidal science. , Ions affect specifically several physicochemical parameters, such as viscosity and surface tension of aqueous solutions and other properties like solubility, − molecular motion, surface charge, adsorption of proteins and other macromolecules. Likewise, ions also affect biological processes, including enzyme activities − and bacterial growth, , in a way which is still unexplained. Particularly interesting is that ion specificity plays a key role at concentrations of 0.1–0.15 M typical of living systems. , At these concentrations electrostatics is screened enough to be comparable with, usually neglected, ionic van der Waals forces. , Thus, biology operates in conditions where ion specificity modulates biomacromolecule interactions.…”

Control of carbon monoxide dehydrogenase orientation by site-specific immobilization enables direct electrical contact between enzyme cofactor and solid surface

“…SPGEs modified with the native and synthetic CODH-Ls were then tested to determine their ET properties using cyclic voltammetry (CV) in phosphate buffer (PB) at pH 7.2. It should be noted that the selection of an appropriate electrolyte for the electrochemical measurements should be based on the assumption that the electrolyte has no effect on the electrochemical characteristics of the enzymes being studied 58 , 59 . Thus, 100 mM PB buffer, at pH 7.2 was used to evaluate the bioelectrochemical properties at the enzyme–electrode interface, since this is the optimal buffer composition and pH for this CODH 49 .…”